In order to provide uniform high-speed multimedia transmission service, a BWA (Broadband Wireless Access) system firstly needs to adopt a well-performed technology counteracting frequency selective fading. As OFDM technology can effectively alleviate the ill influence caused by frequency selective fading, therefore attracts researchers' attention and has been regarded as a first-choice key physical transmission technology of various new wireless standards a long time ago, and research on its standardization and industrialization has been started.
A MMB (Mobile Multimedia Broadcasting) is an important aspect of an application of OFDM technology. Relative to networking mode of a cellular mobile communication system, a MMBS (Mobile Multimedia Broadcasting System) often adopts a mode of single frequency networking. The working environment where a single frequency network terminal receiver is situated is very special and may be roughly classified into two categories. One is a typical multipath fading environment with short time delay and the other is dual strong path wireless environment with large time delay. In order to effectively counteract the unfavorable influence of a multipath environment with large time delay on an OFDM system of MMB, typically a longer cycle prefix is required to be added into a physical layer frame structure of a broadcasting signal. Cycle prefix is a repetition of an effective signal and is used for guaranteeing orthogonality among subcarriers of received OFDM signals. Usually a receiver will discard a prefix cycle, therefore resulting in power waste of sent signals.